Non-invasive evaluation of maldigestion and malaborption

Abstract

A bentiromide test for evaluation of pancreatic function is provided which includes the steps of administering a stable, non-radioactive isotope of PABA along with the bentiromide and measuring the natural PABA and PABA isotope by gas chromatography mass spectroscopy (GC/MS). In a preferred embodiment, xylose is also administered and measured in the sample by GC/MS.

We claim: 
     
       1. A method of using a non-radioactive isotope of PABA capable of being absorbed through a patient's digestive tract and passing into urine or serum for evaluating pancreatic and small bowel function in a patient comprising: a) obtaining a first 0-time fluid sample from the patient and measuring natural PABA concentration therein;   b) administering to said patient a known quantity of bentiromide along with a known quantity of xylose;   c) administering with said bentiromide and xylose a non-radioactive isotope of PABA selected from the group consisting of [ 13  C] 6  -PABA and 2,6-[ 2  H] 2  -PABA, having a molecular weight different from natural PABA;   d) allowing sufficient time for said xylose, bentiromide and PABA isotope to be absorbed through the patient's digestive tract and pass into said fluid;   e) obtaining a second later time sample of said fluid from said patient, and measuring the xylose, natural PABA and isotope PABA therein using gas chromatography mass spectroscopy wherein said PABA measurement specifically measures PABA rather than other arylamines; and   f) comparing said measured amount of natural PABA in said 0-time sample, said administered amounts of xylose, isotope PABA, and bentiromide, and said measured amounts of xylose, natural PABA and isotope PABA in said later-time sample to determine the proportion of administered bentiromide converted to natural PABA in the patient's body, said proportion being indicative of pancreatic function, and said measured amount of xylose is compared with said administered amount of xylose to determine the proportion of xylose absorbed in the digestive tract of said patient, said proportion being indicative of small bowel disease.   
     
     
       2. A method of using a non-radioactive isotope of PABA capable of being absorbed through a patient's digestive tract and passing into urine or serum for screening pancreatic function in a patient comprising: a) obtaining a first 0-time fluid sample from the patient and measuring natural PABA concentration therein;   b) administering to said patient a known quantity of bentiromide;   c) administering with said bentiromide a non-radioactive isotope of PABA selected from the group consisting of [ 13  C] 6  -PABA and 2,6-[ 2  H] 2  -PABA, having a molecular weight different from natural PABA;   d) allowing sufficient time for said bentiromide and PABA isotope to be absorbed through the patient's digestive tract and pass into said fluid;   e) obtaining a second later time sample of said fluid from said patient, and measuring the natural PABA and isotope PABA therein by mass spectroscopy wherein said PABA measurement specifically measures PABA rather than other arylamines; and   f) comparing said measured amount of natural PABA in said 0-time sample, said administered amounts of bentiromide and isotope PABA, and said measured amounts of natural PABA and isotope PABA to determine the proportion of administered bentiromide converted to natural PABA in the patient's body, said proportion being indicative of pancreatic function.   
     
     
       3. The method of claim 2 wherein said fluid samples are serum samples. 
     
     
       4. The method of claim 2 wherein said administered amounts of bentiromide are between about 6 mg and about 7 mg and said administered amounts of isotope PABA are between about 2.0 mg and about 2.5 mg. 
     
     
       5. The method of claim 2 wherein a second isotope of PABA having a molecular weight different from natural PABA and from said administered isotope of PABA is added to said second fluid sample prior to said measurements to provide a standard for said measurements. 
     
     
       6. The method of claim 2 wherein xylose is administered to said patient with said bentiromide and measured in said second fluid sample, and said measured amount of xylose is compared with said administered amount of xylose to determine the proportion of said xylose absorbed in the digestive tract of said patient, said proportion being indicative of small bowel function in said patient. 
     
     
       7. A method of using a non-radioactive isotope of PABA for evaluating pancreatic function in a patient comprising: a) administering to said patient a known quantity of a non-radioactive isotope of bentiromide selected from the group consisting of N-benzoyl-tyrosyl 2,6-[ 2  H] 2  -PABA and N-benzoyl-tyrosyl  13  [C] 6  -PABA having a molecular weight different from natural bentiromide;   b) administering with said isotope of bentiromide a non-radioactive isotope of PABA having a mass different from the PABA portion of said isotope of bentiromide;   c) allowing sufficient time for said isotope of bentiromide to be absorbed through the patient's digestive tract;   d) obtaining a fluid sample from said patient, and measuring the isotopes of PABA therein; and   e) comparing said administered amounts of bentiromide and PABA isotopes and said measured amounts of PABA isotopes in said fluid sample, to determine the proportion of administered isotope bentiromide converted to isotope PABA in the patient's body, said proportion being indicative of pancreatic function.   
     
     
       8. The method of claim 7 wherein said fluid sample is a serum sample. 
     
     
       9. The method of claim 7 wherein said measurements are performed by mass spectroscopy. 
     
     
       10. The method of claim 7 wherein said administered amount of isotope bentiromide is between about 6 mg and about 7 mg. 
     
     
       11. The method of claim 7 wherein xylose is administered to said patient with said isotope bentiromide and measured in said fluid sample, and said measured amount of xylose is compared with said administered amount of xylose to determine the proportion of said xylose absorbed in the digestive tract of said patient, said proportion being indicative of small bowel function in said patient.